In this chapter, you learn what is
input and what are input devices. The keyboard is presented and different
keyboard types are described. You are introduced to various pointing devices,
such as the mouse, trackball, touchpad, pointing stick, joystick, touchscreen,
and pen input. Scanners and reading devices, including optical scanners, optical
readers, magnetic ink character recognition readers, and data collection devices
are explained. You learn about digital cameras, audio input, speech recognition,
video input, and videoconferencing. Finally, input devices for physically
challenged users are explored.

Input is any data or
instructions entered into the memory of a computer. Two types of input are data
and instructions. Data is a collection of unorganized items that can include
words, numbers, pictures, sounds, and video. A computer processes data into
information, which is organized, meaningful, and useful. Instructions can be in
the form of programs, commands, or user responses. A program is a series of
instructions that tells a computer how to perform the tasks necessary to process
data into information. A command is an instruction given to a computer program.
A user response is an instruction you issue to the computer by responding to a
question posed by a computer program. Any hardware component that allows you to
enter data, programs, commands, and user responses into a computer is an input
device.

The keyboard is an input device that
contains keys you press to enter data into a computer. Desktop computer
keyboards usually have from 101 to 105 keys, while keyboards for smaller
computers contain fewer keys. All keyboards have a typing area used to type
letters of the alphabet, numbers, punctuation marks, and other basic characters.
Many desktop computer keyboards also have a numeric keypad designed to make it
easier to enter numbers, function keys programmed to issue commands and
accomplish certain tasks, arrow keys used to move the insertion point (a symbol
on the screen that indicates where the next typed character will display), and
toggle keys that can be switched between two different states.

A standard computer
keyboard sometimes is called a QWERTY keyboard because of the layout of its
typing area. An enhanced keyboard has 12 function keys along the top row, 2 ctrl
keys, 2 alt keys, and a set of arrow and additional keys between the typing area
and the numeric keypad. Cordless keyboards transmit data via infrared light
waves. Keyboards for notebook and handheld computers usually have smaller and
fewer keys than desktop computers. A portable keyboard is a full-sized keyboard
you can attach to and remove from a handheld computer. Some manufacturers have
designed ergonomic keyboards to reduce the chance of workplace injuries. The
goal of ergonomics is to incorporate comfort, efficiency, and safety into the
design of workplace items.

In a graphical user
interface, the pointer is a small symbol on the screen. A pointing device is an
input device that allows you to control the pointer. Common pointing devices
include the mouse, trackball, touchpad, pointing stick, joystick, touch screen,
light pen, and a stylus. A mouse is a pointing device, designed to fit
comfortably under the palm of your hand, that is moved across a flat surface. A
trackball is a stationary pointing device with a ball mechanism on its top. A
touchpad is a flat, rectangular pointing device that is sensitive to pressure
and motion. A pointing-stick is a pressure-sensitive pointing device shaped like
a pencil eraser that is positioned between keys on the keyboard. A joystick is a
vertical lever mounted on a base. A light pen is a handheld device that contains
a light source or can detect light. A touch screen is a touch-sensitive display
on the screen. A stylus looks like a ballpoint pen but uses pressure, instead of
ink, to write text and draw lines. An electronic pen can be used on a graphics
tablet, which consists of a flat, rectangular, electronic plastic board used to
input graphical data.

As you move a mouse across
a flat surface, the movement is translated into signals that are sent to the
computer, and the pointer on the screen also moves. When you move the mouse to
the right, the pointer moves to the right on the screen. For Windows users, the
top of a mouse has at least two buttons and sometimes also a wheel. Generally,
you use a mouse to move the pointer on the screen to an object and then press a
button, or click, to perform a certain action on that object. Other operations
you can perform using a mouse include right-click, double-click, drag,
right-drag, rotate wheel, and press wheel button.

A mechanical mouse has a
rubber or metal ball on its underside. When the ball rolls in a certain
direction, electronic circuits in the mouse translate the movement into signals
that are sent to the computer. For better traction, you should place a
mechanical mouse on a mouse pad. An optical mouse has no moving parts; instead
it uses devices that emit and sense light to detect the mouse’s movement. An
optical mouse can be used on nearly all surfaces, is more precise than a
mechanical mouse, and does not require cleaning. A cordless mouse, or wireless
mouse, is a battery powered device that transmits data using wireless
technology, such as radio waves or infrared light waves. A cordless mouse uses
technology very similar to that of a cordless keyboard.

Voice input is the process
of entering data by speaking into a microphone that is attached to the sound
card on a computer. Voice recognition is the computer’s capability of
distinguishing spoken words. The first voice recognition programs were speaker
dependent. With speaker-dependent software, the computer makes a profile of your
voice, which means you have to train the computer to recognize your voice.
Today, most voice recognition programs use speaker-independent software, which
has a built-in set of word patterns and does not have to be trained to recognize
your voice. Some voice recognition software requires discrete speech, meaning
that you have to speak slowly and separate each word with a short pause. Most
voice recognition products, however, support continuous speech, allowing you to
speak in a flowing conversational tone.

To satisfy the input needs
of many different types of users, handheld computers provide many different ways
to input data. A handheld computer typically includes a basic stylus. With the
stylus, you can enter data using an on-screen keyboard or using handwriting
recognition software that translates handwritten letters and characters into
symbols the computer understands. Other input alternatives available with some
handheld computers include attaching a full-sized keyboard, transferring data
from a desktop computer, using voice input, and attaching a digital camera.

A digital camera is used
to take pictures and store the photographed images digitally instead of on
traditional film. Pictures are stored on a storage medium, such as a floppy
disk, SuperDisk, Clik! disk, PC Card, compact flash card, memory stick, mini-CD,
or microdrive. Many digital cameras allow you to review and edit the images
while they are in the camera. You also can download, or transfer a copy of, the
stored image to a computer. Once on a computer, the pictures can be edited with
photo-editing software, printed, faxed, sent via electronic mail, included in
another document, or posted to a Web site. There are three basic types of
digital cameras. A studio camera is a stationary digital camera used for
professional studio work. A field camera is a portable camera, often used by
photojournalists, that has many lenses and other attachments. A point-and-shoot
camera is more affordable and lightweight and provides acceptable quality
photographic images for the home or small business user.

Video input, or video
capture, is the process of entering a full-motion recording into a computer and
storing the video on a storage medium. Many video devices use analog video
signals. To input video from these devices, the device is plugged into a video
capture card, an expansion card that converts the analog signal into a digital
signal the computer can understand. A digital video (DV) camera is a new
generation of video camera that records video as digital signals, instead of
using analog signals, and therefore does not require a video capture card. Video
files can demand huge amounts of storage space. Video compression reduces the
size of video files by recognizing that only a small portion of an image changes
from frame to frame. Instead of storing every frame in its entirety, a video
compression program might store an initial frame and then store only the changes
from one frame to the next. A video decoder is a card that decompresses video. A
video digitizer can be used to capture an individual frame from a video and save
the still picture in a file.

A PC camera is a DV camera
that allows home users to record, edit, capture video and still images, and make
video telephone calls on the Internet. During a video telephone call, both
parties can see each other as they talk. Although usually placed on top of the
monitor and attached to a computer’s USB port, some PC cameras are portable
and can be used anywhere. A Web cam is a video camera whose output displays on a
Web page. Some Web sites have live Web cams that display still pictures and
update the displayed images at specified time intervals.

Scanners and optical
readers can capture data from a source document, which is the original form of
the data. A scanner is a light-sensing input device that reads printed text and
graphics and then translates the results into a form a computer can use. One of
the more popular scanners is a flatbed scanner, which works similarly to a copy
machine except it creates a file of the document in memory instead of a paper
copy. Many scanners include OCR software, which converts a scanned image into a
text file that can be edited. An optical reader uses a light source to read
characters, marks, and codes and converts them into digital data that a computer
can process. Three types of optical readers are optical character recognition,
optical mark recognition, and bar code scanner. Optical character recognition
(OCR) is a technology that reads typewritten, computer printed, or handwritten
characters from ordinary documents and translates the images into a form that
the computer can understand. Optical mark recognition (OMR) devices read
hand-drawn marks such as circles or rectangles. A bar code scanner uses laser
beams to read bar codes, which are identification codes consisting of vertical
lines and spaces of different widths. Another type of reader, called a
magnetic-ink character recognition (MICR) reader, reads text printed with
magnetized ink and is used almost exclusively by the banking industry.

Whether at work or at
home, it may be necessary to obtain input devices that address physical
limitations. Voice recognition is ideal for blind or visually impaired users,
but several other input devices also are available. A keyguard, which is placed
over the keyboard, allows people with limited hand mobility to rest their hands
on the keyboard and guides a finger or pointing device so that only one key is
pressed. Keyboards with larger keys and on-screen keyboards on which keys are
pressed using a pointing device also can help. Pointing devices such as small
trackballs controlled with a thumb or one finger and head-mounted pointers also
are available for users with motor disabilities. Two new developments are
gesture recognition and computerized implant devices. With gesture recognition
the computer will be able to detect human motions. Computerized devices
implanted in the brain will allow paralyzed individuals to transmit signals to
the computer.

Here you will find additional
information that will expand and enhance your knowledge beyond that contained
in your textbook. Compare this information to what may be provided in a
traditional classroom by your instructor or peers.

Of
the four operations in the information processing cycle – input, process,
output, and storage – input is the operation to which computer users are
most closely linked and on which each subsequent action depends.

Typed
commands use keywords – specific words, phrases, or codes that a program
recognizes as instructions. Keywords are an essential element of
command-driven programs, such as DOS. The problem with keywords is that:

they must be memorized,
and

they must be
entered correctly

This makes
command-driven programs difficult to use. Menu-driven programs and graphical
user interfaces eliminate the problems of having to memorize and correctly
type keywords.

Data entered through
the keyboard averages about one error for every 300 characters, while data
entered more directly, such as with a scanning device, averages only one error
for every 3 million characters. Nevertheless, the keyboard continues to be the
most popular input device. Some special keys – alt,
ctrl, and shift
– almost always are used in combination with other keys. Desktop computer
keyboards generally have two ways to enter numbers – the numeric keypad and
the row of number keys above the alphabetic keys. Think of situations in which
both would be used. The numeric keypad also contains arrow keys, but these
keys are active only when the keypad is turned off. Although the purpose of
function keys varies, some developers have tried to standardize certain keys
(such as using f1 to access
online Help). In addition to the num
lock key, other toggle keys are the caps
lock key and the insert
key. Unlike the caps lock key
on a typewriter, the caps lock
key on a computer keyboard cannot be used to print the special characters on
the keys in the number row.

Keyboards are used
primarily to enter alphanumeric data. Not surprisingly, keyboards for oriental
languages are significantly more complex than the keyboard shown in Figure
5-3. The QWERTY keyboard was devised in 1867 by Christopher Sholes, inventor
of the first practical commercial typewriter. Ironically, Sholes’ intent
when designing the keyboard was to slow typists down; if typists worked too
quickly, keys had a tendency to jam. Many feel the QWERTY keyboard is an
anachronism, and its continued use is counterproductive. A more recent design,
called the Dvorak keyboard (named for August Dvorak, American educator,
1895-1975) places the most frequently used keys in the middle of the typing
area. Studies have shown that trained typists using the Dvorak keyboard are up
to 20 times faster than trained QWERTY typists. Despite this, the Dvorak
keyboard rarely is used. Repetitive stress injury (RSI) afflicts more than 1.8
million people in the United States. A debilitating repetitive stress injury
that plagues some keyboard users is carpal tunnel syndrome. This painful wrist
injury affects sufferers not only when working at the keyboard, but when
performing other tasks as well. The wrist rest on the keyboard in Figure 5-3
is designed to reduce wrist strain.

The original mouse was a
one-button, cigarette-pack shaped device invented by Doug Engelbart in 1964.
Today, many software manufacturers have made the mouse (or a related pointing
device) an essential part of their applications. When the screen is cluttered
or pointer targets are small, however, some experienced users still prefer
keyboard commands if they are offered.

Some people feel that a touchpad
is the most difficult pointing device to use. To satisfy divergent
preferences, several laptop computers include both a pointing stick and
a touchpad.

Although trackballs, touchpads,
and pointing stick devices require less space than a mouse (making them
popular for portable computers), most people find them harder to use. Because
of this a smaller mouse, called Mouse2Go, has been developed for use on a
small pad that clips to the side of a portable computer.

Joystick concepts evolved from
actual use in jet fighter airplanes, where joysticks allowed pilots to control
an aircraft’s movement quickly and precisely.

Although touch screen users
touch a symbol on the screen, it is the location where the touch occurred, not
the symbol contacted, that is important. Because they are so user-friendly,
even people unfamiliar with computers are comfortable with touch screens.

The major advantage of a
mouse is that it is easy to use. The disadvantages are twofold: first, the
mouse requires additional desk space, making it difficult to use in cramped
locations; and second, mouse use demands that a hand be taken from the
keyboard (unlike a pointing stick, which can be used without removing a hand
from the keyboard). When a mouse has two buttons, one is the primary mouse
button and the other is the secondary mouse button. To reverse the functions
of these buttons or change other mouse options in Windows 98, point to
Settings on the Start menu, click Control Panel on the Settings submenu, then
double-click the Mouse icon in the Control Panel window. In the Mouse
Properties dialog box that displays, the Basics tab allows you to change
pointer speed, button selection, and double-click speed.

Since its introduction
in 1965, the mouse has gone through several transformations. Microsoft’s “green
eye” mouse, an early mouse with two buttons, was released in 1983 and now is
a collector’s item. Other interesting mouse variations include Spectrum’s
RingMouse (which uses infrared to point), Interlink’s wireless mouse (often
used for presentations), and Interlink’s DuraPoint PC mouse (an incredibly
durable mouse that gained the Pentagon’s interest). A new mouse from
Immersion Corporation provides tactile sensations, with an internal motor that
allows users to “feel” the desktop. The mouse – which senses cursor
position, identifies screen objects, and sends pulses to a motor beneath the
surface of the mouse – lets users feel icons, sense Web links, or bump
through menu commands.

Some experts believe
voice input eventually will be the most common way to operate a computer.
Speech recognition is particularly welcome to people with certain
disabilities. Although speech recognition continues to improve, developers
admit that advertisements touting high accuracy rates generally assume a
standard vocabulary. Specialized words, regional accents, and local dialects
reduce accuracy. Even a 95 percent accuracy rate, meaning that on average 1
out of every 20 words is wrong, may not inspire confidence. (Imagine if, in
conversation, every 20th word spoken was misinterpreted.)
Nevertheless, voice recognition systems are gaining in popularity.

Instead of using a
keyboard, with most handheld computers you write or make selections on the
computer screen with a stylus. Although a handheld computer typically includes
a basic stylus, you can buy more elaborate models that have a ballpoint pen at
one end and a stylus at the other.

Some manufacturers use
dots per inch to represent a digital camera’s resolution, or the sharpness
and clarity of the image it produces. Dots per inch (DPI) is
the number of pixels in an inch of screen display. A pixel is a single
point in an electronic image. Digital cameras for the consumer range from 640
x 480 dpi to 1,792 to 1,200 dpi. The actual photographed resolution is called
the optical resolution. Some manufacturers also state enhanced
resolution, which uses a special formula to add pixels between those
generated by the optical resolution. With the price of digital cameras
decreasing, will the era of film-based cameras soon come to an end? Why or why
not?

Video input is used in a
variety of ways, from developing training films to creating presentation
enhancements. Video input also has been used in the workplace to record
(sometimes secretly) office or assembly-line workers in an effort to find
possible quality or efficiency problems. Do you think this secret recording is
ethical? Why or why not?

Estimates suggest that
currently more than 9,000 Web sites use Web cams. Web cams are used to put
everything from college dorm rooms to taxi cabs on the Web. The first personal
Web page to use a Web cam was the JenniCam, which showed the daily life of a
college co-ed. The site started in 1996 as a project for a computer class and
still receives more than 4.5 million hits a day. Web cams also have more
practical uses. Recently, some day-care centers have installed Web cams so
parents can use the center’s Web page to check on their children. This use
of Web cams, however, has not been without controversy. Due to the usually
slower speeds of Web cam videos, it can be difficult for parents to tell the
difference between a day care worker’s loving pat on the head and a rap on
the noggin.

In general, scanners
and reading devices increase input accuracy and efficiency by reducing the
role of the weak link in the input process – the human operator. Optical
readers are highly specialized. Devices that read one set of codes, marks, or
characters may not be able to read another.

An optical mark reader identifies the position, not the shape, of a mark. You
may be familiar with optical marks from tests in which you use a pencil to
fill in ovals or rectangles that represent the answers.

Bar codes minimize input
errors, keep inventories up to date, help to track sales trends, and eliminate
the need to price individual items. The identifying numbers on a UPC code can
be entered if the scanner fails. This number is not the item’s cost
– prices are obtained from a database when the item is scanned. Some
consumer groups, however, claim price databases not always are accurate, and
that the absence of individual item pricing makes comparing costs difficult.

The MICR font, adopted by the
American Banking Association in the 1950s, is standard throughout the banking
industry. The special shapes of MICR characters make them easier for a machine
to read. MICR readers can interpret magnetic characters even if someone has
written over them. If the magnetic ink on a check is damaged, however, the
data must be typed into the system. The importance of MICR readers to the
banking industry is staggering – half of the U.S. population would be needed
to process checks if it were done manually.

Some input aids for
physically challenged people are relatively simple (such as keyguards), while
others are much more sophisticated (such as head-mounted pointers).
Chin-operated joysticks also are available. Another input system, called
Eyegaze or ERICA (Eyegaze Response Interface Computer Aid), was developed by
Thomas Hutchinson of the University of Virginia, who as a boy was paralyzed
temporarily by an accident. With a camera mounted on the computer and directed
at a user’s eye, the Eyegaze system can determine to within a ¼ inch where
on the screen a user is looking. By staring at the spot for about ¼ second, a
user can activate a choice. Adaptive technology has given many people their
best opportunity to communicate, work, and play. As a six-year-old victim of
cerebral palsy said in her first message, “It’s about time.”